A vehicle is commonly provided with a wiper assembly in order to wipe away rain, snow, or dirt accumulated on a windshield glass of the vehicle, thereby ensuring visibility for the driver. The wiper assembly often includes a spraying device that sprays liquid for facilitating the removal of contaminants and lubricating the movement of a wiper blade on the windshield glass.
The wiper assembly often comprises a motor assembly generating driving force with electric input, linkage members for transferring the driving force between each member, and a wiper arm assembly, which actually cleans the windshield while reciprocating on the windshield.
The motor assembly includes a wiper motor and a gear box consisting of a set of gears that changes the motor rotation speed into an appropriate rotational speed. A reciprocating speed of the wiper arm assembly can be adjusted by controlling the current into a serial-wounded field coil and a shunt-wounded field coil of the wiper motor.
The linkage members, which transfer the driving force and interlock a left wiper arm and a right wiper arm, are typically composed of a motor-driven arm installed to a motor shaft, wiper arm shafts, wiper driving arms attached to one end of the wiper arm shafts, and connecting rods to link the motor-driven arms with the wiper driving arms. The wiper arm assembly includes a couple of wiper arms, one end of which is rotatably joined to the wiper arm shaft. Detachably coupled to the other end of the wiper arm is a wiper blade made of rubber material, which is in direct contact with the windshield.
The wiper motor is generally disposed below a hood panel with sufficient void space between the hood panel and the wiper motor in order to ensure pedestrian safety in the event of a collision. As another safety feature, the wiper arm shaft is furnished with a notch that acts as a weak spot to allow the wiper arm shaft to easily break in the event of a collision with a pedestrian, thereby minimizing injury to the pedestrian.
However, the above wiper assembly is disadvantageous in that there is an unpleasant vibration and noise during the operation of the wiper assembly because of the undesirable arrangement of the wiper driving arms and the motor-driven arm. Namely, because the wiper driving arm and the motor-driven arm are not positioned at the same height, a connecting rod interposed between the wiper driving arms and the motor-driven arm is placed at a slant, which generates unpleasant vibration and noise at both joints of the connecting rod.
Moreover, rain or other contaminants enter the gap between the wiper arm shaft and the wiper driving arm, resulting in wiper assembly malfunction.